Nuclear symmetry energy and the PREX-CREX neutron skin puzzle within the KIDS framework

Abstract

I briefly review the KIDS theoretical framework for the nuclear equation of state (EoS) and energy density functional (EDF), I discuss recent results for the curvature parameter of the symmetry energy, and I address the PREX-CREX puzzle. I show that it is possible to obtain EDF models which can reproduce both PREX-II and CREX results each within its respective error bars. Such EDFs correspond to EoSs which soften towards low densities, as could be attributed to clusterization. Before such a scenario is considered viable, the dipole polarizability should also be examined.

Bayesian refinement of covariant energy density functionals

“…Plans are currently under way to enlarge the isovector sector of the covariant EDFs in the hope of breaking such a correlation. However, the challenge to reconcile both measurements appears to go beyond the class of covariant EDFs considered in this work [76][77][78][79][80]. Only time will tell whether the resolution of this puzzle is hiding behind the large experimental error bars or whether it demands a more ingenious solution.…”

“…As such, one must conclude that-at present-no single theoretical framework can reproduce simultaneously the PREX and CREX results [76][77][78][79][80].…”

Dense Nuclear Matter Equation of State from Heavy-Ion Collisions

“…However, the 48 Ca value is much closer to the theoretical predictions. The discrepancies between the two results and the expectations from models have not been resolved, and the CREX collaboration has not released official values for the slope of the symmetry energy or symmetry pressure, even though there have been many attempts by outside groups to resolve the apparent discrepancies between the two skin measurements [390][391][392].…”